Step 1Place the bellflower roots in a large bowl and pour in enough hot water to cover. Soak overnight to reconstitute; drain. Carefully shred the softened pieces by inserting the end of a paper clip or a needle into one end of the bellflower root and tearing the root into lengthwise strips. They should be about one-eighth-inch thick. Divide the larger pieces into three strips and the smaller pieces in half.
Step 2Place the shredded bellflower root back into a bowl and, using your hands, mix thoroughly with the teaspoon of coarse salt. Let stand for 10 minutes. Soak in a fresh change of water for 10 minutes. Drain, then vigorously squeeze the roots until as much water is rendered as possible.
Step 3In a large saucepan, heat the vegetable oil over medium heat. Add the minced garlic, soy sauce and sugar. When the mixture is hot and the garlic is fragrant, add the bellflower roots. Saute for 12 minutes until the roots soften, stirring occasionally.
Step 4Remove from the heat and add the green onions. Season with salt and pepper and garnish with the crushed and roasted sesame seeds.